“Private equity funds continue to make a very strong push in the oil and gas sector,” said Roberge. “The private equity deal makers, who used to largely play in the midstream space, are now heavily involved in exploration and production, shale plays, and oil field services and equipment sector.”

For deals valued at over $50 million, the second quarter 2011 activity included 11 midstream deals accounting for $19.9 billion compared with 6 deals worth $3.4 billion in the same period last year. Upstream transactions led M&A activity during the most recent quarter with 26 deals.

Seven of the top 10 deals by value in second quarter 2011 were associated with shale plays, and four of those seven involved upstream assets.